Systems and methods for configuring components in a minimally invasive instrument

ABSTRACT

A catheter system comprises an elongate flexible catheter and a support structure mounted on the catheter. The support structure comprises a first alignment feature and a second alignment feature. The first alignment feature is configured to mate with a first sensor component and the second alignment feature configured to mate with a second sensor component. When the system further comprises a first sensor component mated with the first alignment feature and a second sensor component mated with the second alignment feature, the first sensor component is fixed relative to the second sensor component in at least one degree of freedom at the support structure by the first and second alignment features.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/964,724, filed on Aug. 12, 2013, which claims the benefit of U.S.Provisional Application 61/682,976 filed on Aug. 14, 2012, both of whichare incorporated by reference herein in their entirety.

FIELD

The present disclosure is directed to systems and methods for minimallyinvasive surgery, and more particularly to systems and methods forconfiguring components in a minimally invasive instrument.

BACKGROUND

Minimally invasive medical techniques are intended to reduce the amountof tissue that is damaged during diagnostic or surgical procedures,thereby reducing patient recovery time, discomfort, and deleterious sideeffects. Such minimally invasive techniques may be performed throughnatural orifices in a patient anatomy or through one or more surgicalincisions. Through these natural orifices or incisions clinicians mayinsert surgical instruments to reach a target tissue location. To reachthe target tissue location, the minimally invasive surgical instrumentsmay navigate natural or surgically created connected passageways inanatomical systems, such as the lungs, the colon, the intestines, thekidneys, the heart, the brain, the circulatory system, or the like.Navigational assist systems help the clinician route the surgicalinstruments and avoid damage to the anatomy. These systems canincorporate the use of sensors to more accurately describe the shape,pose, and location of the surgical instrument in real space or withrespect to previously recorded or concurrently gathered images. In adynamic anatomical system and/or in an anatomical region dense with manyanatomical passageways, accurately determining the shape, pose, andlocation of the surgical instrument may depend, at least in part, uponprecision in the relative placement of sensor systems, steering systems,and imaging components. Improved systems and methods are needed fortight control of the relative placement of the systems and components ofminimally invasive instruments.

SUMMARY

The embodiments of the invention are summarized by the claims thatfollow the description.

In one embodiment, a catheter system comprises an elongate flexiblecatheter and a support structure mounted on the catheter. The supportstructure comprises a first alignment feature and a second alignmentfeature. The system further comprises a first sensor component matedwith the first alignment feature and a second sensor component matedwith the second alignment feature. The first sensor component is fixedrelative to the second sensor component in at least one degree offreedom at the support structure by the first alignment feature.

In another embodiment, a catheter system comprises an elongate flexiblecatheter and a first support structure mounted on the catheter. Thefirst support structure comprises a first alignment feature and a secondalignment feature. The system further comprises a second supportstructure mounted on the catheter. The second support structurecomprises a third alignment feature and a fourth alignment feature. Thesystem further comprises a first sensor component comprising a firstportion mated with the first alignment feature and a second portionmated with the third alignment feature. The system further comprises asteering wire mated with the second alignment feature and the fourthalignment feature. The first sensor component is fixed relative to thesteering wire at the first support structure in at least one degree offreedom by the first alignment feature and the second alignment feature.The first sensor component is fixed relative to the steering wire at thesecond support structure in at least one degree of freedom by the thirdalignment feature and the fourth alignment feature.

In another embodiment, a method comprises providing a flexible catheter.The flexible catheter comprises a first sensor component, a secondsensor component, and a first support structure. The first supportstructure comprises a first alignment feature and a second alignmentfeature. The first sensor component is fixed in a predetermined positionrelative to the second sensor component at the first support structure.The method further comprises acquiring data from the first sensorcomponent and the second sensor component. The method also comprisesdetermining a pose of at least a portion of the flexible catheter basedon the predetermined position and the data from the first sensorcomponent and the second sensor component.

BRIEF DESCRIPTIONS OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isemphasized that, in accordance with the standard practice in theindustry, various features are not drawn to scale. In fact, thedimensions of the various features may be arbitrarily increased orreduced for clarity of discussion. In addition, the present disclosuremay repeat reference numerals and/or letters in the various examples.This repetition is for the purpose of simplicity and clarity and doesnot in itself dictate a relationship between the various embodimentsand/or configurations discussed.

FIG. 1 is a diagrammatic top view of robotic surgical system, inaccordance with embodiments of the present disclosure.

FIG. 2 illustrates an endoscopy system utilizing aspects of the presentdisclosure.

FIG. 3a is an illustration of an exploded probe assembly according to anembodiment of the present disclosure.

FIG. 3b is a cross-sectional view of an alignment support structure ofthe catheter of FIG. 3 a.

FIG. 3c is a cross-sectional view of another alignment support structureof the catheter of FIG. 3 a.

FIG. 3d is a perspective view of the alignment support structure of FIG.3 c.

FIG. 3e is a cross-sectional view of the probe of FIG. 3 a.

FIG. 4 is a perspective view of an alternative proximal supportstructure according to an embodiment of the disclosure.

FIG. 5 is an end view of the proximal support structure of FIG. 4

FIG. 6 is a flowchart describing a method for determining the pose of aportion of a probe in three-dimensional space.

FIG. 7 is a perspective view of a probe according to an embodiment ofthe disclosure.

DETAILED DESCRIPTION

In the following detailed description of the aspects of the invention,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. However, it will be obviousto one skilled in the art that the embodiments of this disclosure may bepracticed without these specific details. In other instances well knownmethods, procedures, components, and circuits have not been described indetail so as not to unnecessarily obscure aspects of the embodiments ofthe invention. And, to avoid needless descriptive repetition, one ormore components or actions described in accordance with one illustrativeembodiment can be used or omitted as applicable from other illustrativeembodiments.

The embodiments below will describe various instruments and portions ofinstruments in terms of their state in three-dimensional space. As usedherein, the term “position” refers to the location of an object or aportion of an object in a three-dimensional space (e.g., three degreesof translational freedom along Cartesian X,Y,Z coordinates). As usedherein, the term “orientation” refers to the rotational placement of anobject or a portion of an object (three degrees of rotationalfreedom—e.g., roll, pitch, and yaw). As used herein, the term “pose”refers to the position of an object or a portion of an object in atleast one degree of translational freedom and to the orientation of thatobject or portion of the object in at least one degree of rotationalfreedom (up to six total degrees of freedom). As used herein, the term“shape” refers to a set of poses, positions, or orientations measuredalong an object.

Referring to FIG. 1 of the drawings, a robotic surgical system isgenerally indicated by the reference numeral 100. As shown in FIG. 1,the robotic system 100 generally includes a surgical manipulatorassembly 102 for operating a surgical instrument 104 in performingvarious procedures on the patient P. The assembly 102 is mounted to ornear an operating table O. A master assembly 106 allows the surgeon S toview the surgical site and to control the slave manipulator assembly102.

The master assembly 106 may be located at a surgeon's console C which isusually located in the same room as operating table O. However, itshould be understood that the surgeon S can be located in a differentroom or a completely different building from the patient P. Masterassembly 106 generally includes an optional support 108 and one or morecontrol device(s) 112 for controlling the manipulator assemblies 102.The control device(s) 112 may include any number of a variety of inputdevices, such as joysticks, trackballs, data gloves, trigger-guns,hand-operated controllers, voice recognition devices, body motion orpresence sensors, or the like.

In alternative embodiments, the robotic system may include more than oneslave manipulator assembly and/or more than one master assembly. Theexact number of manipulator assemblies will depend on the surgicalprocedure and the space constraints within the operating room, amongother factors. The master assemblies may be collocated, or they may bepositioned in separate locations. Multiple master assemblies allow morethan one operator to control one or more slave manipulator assemblies invarious combinations.

A visualization system 110 may include an endoscope system such that aconcurrent (real-time) image of the surgical site is provided to surgeonconsole C. The concurrent image may be, for example, a two- orthree-dimensional image captured by an imaging probe positioned withinthe surgical site. In this embodiment, the visualization system 110includes endoscopic components that may be integrally or removablycoupled to the surgical instrument 104. In alternative embodiments,however, a separate endoscope attached to a separate manipulatorassembly may be used to image the surgical site. Alternatively, aseparate endoscope assembly may be directly operated by a user, withoutrobotic control. The endoscope assembly may navigation control devicesinclude active steering devices (e.g., via teleoperated steering wires)or passive steering devices (e.g., via guide wires or direct userguidance). The visualization system 110 may be implemented as hardware,firmware, software, or a combination thereof, which interacts with or isotherwise executed by one or more computer processors, including, forexample the processor(s) of a control system 116.

A display system 111 may display an image of the surgical site andsurgical instruments captured by the visualization system 110. Thedisplay 111 and the master control device(s) 112 may be oriented suchthat the relative positions of the imaging device in the scope assemblyand the surgical instruments are similar to the relative positions ofthe surgeon's eyes and hand(s) so the operator can manipulate thesurgical instrument 104 and the master control device(s) 112 as ifviewing the workspace in substantially true presence. True presencemeans that the displayed tissue image appears to an operator as if theoperator was physically present at the imager location and directlyviewing the tissue from the imager's perspective.

Alternatively or additionally, display system 111 may present images ofthe surgical site recorded and/or modeled preoperatively using imagingtechnology such as computerized tomography (CT), magnetic resonanceimaging (MRI), fluoroscopy, thermography, ultrasound, optical coherencetomography (OCT), thermal imaging, impedence imaging, laser imaging,nanotube X-ray imaging, or the like. The presented preoperative imagesmay include two-dimensional, three-dimensional, or four-dimensional(including e.g., time based or velocity based information) images.

In some embodiments, the display system 111 may display a virtualnavigational image in which the actual location of the surgicalinstrument is registered (e.g., dynamically referenced) with previouslyrecorded or concurrent images to present the surgeon S with a virtualimage of the internal surgical site at the location of the tip of thesurgical instrument.

In other embodiments, the display system 111 may display a virtualnavigational image in which the actual location of the surgicalinstrument is registered with prior images (including preoperativelyrecorded images) or concurrent images to present the surgeon S with avirtual image of a surgical instrument at the surgical site. An image ofa portion of the surgical instrument may be superimposed on the virtualimage to assist the surgeon controlling the surgical instrument.

As shown in FIG. 1, a control system 116 includes at least one processor(not shown), and typically a plurality of processors, for effectingcontrol between the slave surgical manipulator assembly 102, the masterassembly 106, the visualization system 110, and the display system 111.The control system 116 also includes programmed instructions (e.g., acomputer-readable medium storing the instructions) to implement some orall of the methods described herein. While control system 116 is shownas a single block in the simplified schematic of FIG. 1, the system maycomprise a number of data processing circuits (e.g., on the slavesurgical manipulator assembly 102 and/or on the master assembly 106),with at least a portion of the processing optionally being performedadjacent the slave surgical manipulator assembly, a portion beingperformed the master assembly, and the like. Any of a wide variety ofcentralized or distributed data processing architectures may beemployed. Similarly, the programmed instructions may be implemented as anumber of separate programs or subroutines, or they may be integratedinto a number of other aspects of the robotic systems described herein.In one embodiment, control system 116 supports wireless communicationprotocols such as Bluetooth, IrDA, HomeRF, IEEE 802.11, DECT, andWireless Telemetry.

In some embodiments, control system 116 may include one or more servocontrollers to provide force and torque feedback from the surgicalinstruments 104 to one or more corresponding servomotors for the controldevice(s) 112. The servo controller(s) may also transmit signalsinstructing manipulator assembly 102 to move instruments which extendinto an internal surgical site within the patient body via openings inthe body. Any suitable conventional or specialized servo controller maybe used. A servo controller may be separate from, or integrated with,manipulator assembly 102. In some embodiments, the servo controller andmanipulator assembly are provided as part of a robotic arm cartpositioned adjacent to the patient's body.

Each manipulator assembly 102 supports a surgical instrument 104 and maycomprise a serial kinematic chain of one or more non-servo controlledlinks (e.g., one or more links that may be manually positioned andlocked in place, generally referred to as a set-up structure) and arobotic manipulator. The robotic manipulator assembly 102 is driven by aseries of actuators (e.g., motors). These motors actively move therobotic manipulators in response to commands from the control system116. The motors are further coupled to the surgical instrument so as toadvance the surgical instrument into a naturally or surgically createdanatomical orifice and to move the distal end of the surgical instrumentin multiple degrees of freedom, which may include three degrees oflinear motion (e.g., linear motion along the X, Y, Z Cartesian axes) andthree degrees of rotational motion (e.g., rotation about the X, Y, ZCartesian axes). Additionally, the motors can be used to actuate anarticulatable end effector of the instrument for grasping tissue in thejaws of a biopsy device or the like.

FIG. 2 illustrates a minimally invasive surgical system 200 utilizingaspects of the present disclosure. The system 200 includes a minimallyinvasive assembly 202, an imaging system 204, a tracking system 206, anda drive system 208. The minimally invasive surgical system 200 may beincorporated into a robotic surgical system, such as system 100 (e.g.,as part of instrument 104), as part of the visualization and displaysystem. Alternatively, the minimally invasive surgical system 200 may beused for non-robotic exploratory procedures or in procedures involvingtraditional manually operated surgical instruments, such as laparoscopicinstruments without robotic control (e.g., systems in which drive system208 includes handles, triggers, or other interface elements for directlymanipulating catheter 210), or “hybrid” procedures in which both roboticand non-robotic controls are provided and/or employed.

The minimally invasive assembly 202 includes an elongated flexiblecatheter 210 having a distal end 212 and a proximal end 214. Thecatheter 210 includes a body wall 211 which defines a centraloperational passageway 222 through the catheter 210. A central axis A1extends longitudinally through the central operational passageway 222.The passageway 222 is sized to receive an operational component such asa flexible probe 216. The flexible probe 216 may be, for example, animaging probe.

The flexible catheter 210 includes a passively flexible portion 218 anda steerable flexible portion 220. As the catheter 210 is advancedthrough an anatomical lumen, the passive portion 218 bends or curvespassively in response to external forces. The steerable portion 220includes an integrated mechanism for operator control of instrumentbending as will be described further below.

The passive portion 218 can have an outer diameter that is larger thanthe outer diameter of the steerable portion 220, for example toaccommodate components in the passive portion that do not extend intothe steerable portion, as described further below. In one example, theouter diameter of the passive portion may be approximately 5 mm. Thesmaller diameter of the steerable portion 220 can allow it to navigatesmaller body lumens that may not be accessible by the proximal bodyportion. In another example, the outer diameter of the steerable portionmay be approximately 3 mm.

During a minimally invasive surgical procedure, accurate registration ofthe probe (e.g., an imaging probe) to images of a patient anatomy(including prerecorded, schematic, or concurrent images) relies uponassumptions about the position and relative motion of sensors and othercomponents associated with the probe and its guiding catheter. For theassumptions to be accurate, a precise determination of the relativesensor poses is desirable. As described below, the structure of theguide catheter and the probe can limit the relative motion of sensors,catheter steering devices, and imaging components to provide consistentand reliable information about the relative sensor poses, positions,and/or orientations.

FIGS. 3a, 3b, 3c, 3d, and 3e illustrate a probe assembly 250 includingan elongated flexible catheter 252 with a body wall 254 defining acentral operational passageway 256 through the catheter. A central axisA2 extends longitudinally through the central operational passageway256. The passageway 256 is sized to receive a flexible probe 258. Thecatheter 252 includes a passively flexible portion 260, a steerableflexible portion 262, a proximal alignment support structure 264 and adistal alignment support structure 265. In this embodiment, thealignment support structures 264, 265 of the catheter 252 are precisionmachined, molded, or otherwise manufactured to control the relativeposition/alignment of various sensors and steering wires, thus reducingthe geometric variability that could otherwise occur duringmanufacturing and/or use of catheter 252. Reducing this variabilityimproves the accuracy of the pose and shape calculations that rely uponassumptions about the relative locations of the sensors and steeringwires. In alternative embodiments, a single support structure, either atthe proximal or distal end of the steering portion may be used.

In this embodiment, the proximal support structure 264 and the portions260, 262 of the catheter 252 are serially aligned, with the proximalsupport structure coupled between the passive portion 260 and thesteerable portion 262. For example, one end of the proximal supportstructure 264 may abut or overlap the distal end of the passive portion260 and the other end may abut or overlap the proximal end of thesteerable portion 262. In alternative embodiments, the proximal supportstructure 264 may be a ring that slides over and becomes affixed to adistal section of the passive portion 260. Other constructions that fixthe proximal support structure 264 relative to the passive portion 260and the steerable portion 262 may also be suitable. Although in certainspecific embodiments the support structures may be coupled to thepassive and steerable portions as described, in other embodiments, thesupport structures may be positioned anywhere along the catheter. Invarious embodiments, the support structures 264, 265 may be integratedwithin, affixed on, or otherwise mounted to the catheter 210.

As shown in FIG. 3b , the proximal support structure 264 includes a bodywall portion 267. The support structure 264 includes alignment featuresthat can be used to fix the position and orientation of operationalcomponents, such as sensors and/or steering wires that extend within thesupport structure. For example, a passageway 266 extends longitudinallythrough or partially through the body wall 267. The passageway 266 isradially offset from and generally parallel to the central axis A2. Thepassageway 266 is sized to mate with a sensor component 268 which mayextend the length of or a partial length of the support structure 264.Sensor component 268 can be glued, press-fit, or otherwise fixed withinat least a portion of passageway 266, thereby precisely positioning andorienting sensor component 268 within support structure 264. As usedherein, the term “fixed” is generally used to describe a position ororientation that varies within a limited range during normal catheterand probe use. Note that while passageway 266 is depicted and describedas an alignment feature for sensor component 268, in various otherembodiments, such alignment feature can include a notch, groove,ridge(s), pocket, or any other feature within or on an internal/externalsurface of body wall 267.

The support structure 264 further includes alignment features such asnavigation passageways 270 sized to receive navigation control devices,such as steering wires 272. The passageways 270 are radially offset fromand generally parallel to the central axis A2. In this embodiment, thepassageways 270 are generally evenly spaced in a radial pattern aboutthe axis A2. In alternative embodiments, there may be fewer or morepassageways 270 to accommodate fewer or more steering wires, and thepassageways may be in various symmetric or non-symmetric configurations,at equal or varying radial distances from axis A2. Steering wires 272are slidably mated within the passageways 270, which constrain theposition and orientation of the steering wires within support structure264. Note that while passageways 270 are depicted and described asalignment features for the steering wires 272, in various otherembodiments, such alignment feature can include a notch, groove,ridge(s), pocket, or any other feature within or on an internal/externalsurface of body wall 267.

The proximal support structure 264 can also include a passageway 274sized to mate with a sensor component 276. The passageway 274 isradially offset from and generally parallel to the axis A2. The sensorcomponent 276 may be glued or otherwise fixed at least partially withinthe passageway 274 to limit movement in one or more degrees of freedom,including lateral movement (e.g., in the X-Y coordinate plane),longitudinal movement (e.g., in the Z-coordinate direction), and roll(e.g., about the Z-coordinate direction) of the sensor component 276relative to the proximal support structure 264. In another embodiment,the sensor component 276 may have cross section shaped like a keystructure that matches a key-hole shape in passageway 274 to limit theroll movement (e.g., rotation around the Z-coordinate direction) of thesensor 276 relative to the proximal support structure 264. Note thatwhile passageway 274 is depicted and described as an alignment featurefor the sensor component 276, in various other embodiments, suchalignment feature can include a notch, groove, ridge(s), pocket, or anyother feature within or on an internal/external surface of body wall267.

Thus, passageways 266, 270, and 274 control the positioning andorientation of sensor component 268, steering wires 272, and sensorcomponent 276 relative to each other within support structure 264.Furthermore, passageways 266, 270, and 274 control the positioning andorientation of sensor component 268, steering wires 272, and sensorcomponent 276 relative to central axis A2. Therefore, by accuratelymanufacturing support structure 264, the positioning and orientation (atsupport structure 264) of sensor component 268, steering wires 272, andsensor component 276 relative to each other and/or central axisA2/central operational passageway 256 can be accurately characterizedand controlled within catheter 210. This precise positional andorientation control in turn enables accurate sensor monitoring andcatheter control, due to the close correlation between the actualpositions/orientations of sensor component 268, steering wires 272, andsensor component 276 (relative to each other and/or central axis A2) andthe expected positions/orientations used in the algorithms forcontrolling and/or detecting position, shape, and/or pose of catheter210. The proximal support structure 264 may be formed of a materialsufficiently rigid to maintain the fixed spatial displacements of thepassageways 266, 270, and 274. Suitable materials may include metals,rigid polymer materials, or ceramics. The proximal support structure 264is generally more rigid than the flexible catheter portions 260, 262. Inmany embodiments, the rigidity and the generally shorter length ofsupport structure 264 relative to catheter portions 260 and 262 canallow support structure 264 to be produced with significantly tighterdimensional tolerances than would be possible within catheter portions260 and 262, thereby enabling greater placement accuracy of sensorcomponent 268, steering wires 272, and sensor component 276 withincatheter 210 than would be possible from relying on features withincatheter portions 260 and 262.

In this embodiment, the distal support structure 265 is coupled to thedistal end of the steerable portion 262. For example, the proximal endof the distal support structure 265 may abut or overlap the distal endof the steerable portion 262. In alternative embodiments, the distalsupport structure 265 may be a ring that slides over or into and becomesaffixed to a distal section of the steerable portion 262. Otherconstructions that fix the distal support structure 265 relative to thesteerable portion 262 may also be suitable.

As shown in FIG. 3c , the distal support structure 265 includes a bodywall portion 278. The support structure 265 includes alignment featuresthat can be used to fix the position and orientation of operationalcomponents, such as sensors and/or steering wires that extend within thesupport structure. For example, the distal support structure 265 furtherincludes navigation passageways 280 sized to mate with the navigationcontrol devices, such as the steering wires 272. The passageways 270 areradially offset from and generally parallel to the central axis A2. Inthis embodiment, the passageways 280 are generally evenly spaced in aradial pattern about the axis A2. In alternative embodiments, there maybe fewer or more passageways 280 to accommodate fewer or more steeringwires, and the passageways may be in various symmetric or non-symmetricconfigurations, at equal or varying radial distances from axis A2.Steering wires 272 are positioned within passageways 280, whichconstrain the position and orientation of the steering wires withinsupport structure 265. In some embodiments, steering wires can besecured within passageways 280 (e.g., via adhesive, soldering, clamping,or attached to attachment features within or around passageways 280). Inother embodiments, steering wires can be secured to support structure265 at a location outside of passageways 280.

The distal support structure 265 also includes a sensor alignmentfeature, such as a passageway 282 sized to mate with the sensorcomponent 276. The passageway 282 is radially offset from and generallyparallel to the axis A2. The sensor component 276 may be glued orotherwise fixed at least partially within the passageway 282 to limitmovement in at least one degree of freedom including for example,lateral movement (e.g., in the X-Y coordinate plane) longitudinalmovement (e.g., in the Z-coordinate direction), and roll (e.g., aboutthe Z-coordinate direction) of the sensor component 276 relative to thedistal support structure 264.

Thus, passageways 280, 282 control the position and orientation ofsteering wires 272 and sensor component 276 relative to each otherwithin support structure 265. Furthermore, passageways 280 and 282control the positioning and orientation of steering wires 272 and sensorcomponent 276 relative to central axis A2. Therefore, by accuratelymanufacturing support structure 265, the positioning and orientation (atsupport structure 265) of steering wires 272 and sensor component 276relative to each other and/or central axis A2/central operationalpassageway 265 can be accurately characterized and controlled withincatheter 210. In a similar manner to that noted above with respect tosupport structure 264, this precise positional and orientation controlin turn enables accurate sensor monitoring and catheter control, due tothe close correlation between the actual positions/orientations ofsteering wires 272 and sensor component 276 (relative to each otherand/or central axis A2) and the expected positions/orientations used inthe algorithms for controlling and/or detecting position, shape, and/orpose of catheter 210. The distal support structure 265 may be formed ofa material sufficiently rigid to maintain the fixed spatialdisplacements of the passageways 280, 282. Suitable materials mayinclude metals, rigid polymer materials, or ceramics. The distal supportstructure 265 is generally more rigid than the flexible catheterportions 260, 262. Because the support structures 264, 265 are generallymore rigid than the rest of the catheter, locating them in limitedlocations, such as at proximal and distal ends of the steerable portionof the catheter 252, allows greater flexibility and steerability for thelength of the steerable portion of the catheter between the supportstructures. Furthermore, in many embodiments, the rigidity and thegenerally shorter length of support structure 265 relative to catheterportion 262 can allow support structure 265 to be produced withsignificantly tighter dimensional tolerances than would be possiblewithin catheter portion 262, thereby enabling greater placement accuracyof steering wires 272, and sensor component 276 within catheter 210 thanwould be possible from relying on features within catheter portions 260and 262.

As shown in FIG. 3d , the distal support structure 265 can furtherinclude ports 338 through which an adhesive material (not shown) may beplaced to adhere the sensor component 276 to the support structure 265to fix the sensor component relative to the support structure.

The proximal support structure 264 has an outer diameter D1, and thedistal support structure 265 has an outer diameter D2. The diameter D1is generally larger than the diameter D2 to accommodate the sensor 268that extends within the proximal support structure 264. The passageways280, 282 extend through the body wall portion 265 with the same radialspacing from the axis A2 as the respective passageways 270, 274 in theproximal support structure 264. Alternatively, the passageways 280, 282in the distal support structure 265 may be spaced a differentpredetermined distance from the axis A2. For example, they may be spacedcloser to the axis A2 to accommodate the smaller diameter of thesteerable portion 265.

The overall length of the catheter 252 may be approximately 60 to 80 cm,although longer or shorter catheters may be suitable. The steerable bodyportion 262 may have a length of approximately 10 to 20 cm. In variousembodiments, the lengths of the steerable and passive portions of thecatheter 252 may be longer or shorter.

The passive flexible portion 260 of the catheter 252 may have anextruded construction with channels for the operational passageway 256,the steering wires 272, and/or the sensors 268, 276. Similarly, thedistal flexible portion 262 of the catheter 252 may have an extrudedconstruction with channels for the operational passageway 256, thesteering wires 272, and/or the sensor 276. Alternatively, the flexibleportions 260, 262 may have a multilayer construction (e.g., a set ofcoaxial catheters sandwiching tubes to direct the steering wires orsensors).

The steering wires 272 extend through the passive portion 260 of thecatheter 252, through the passageways 270 of the proximal supportstructure 264, and through the steerable portion 262 of the catheter252. The steering wires 272 may terminate in the passageways 280 of thedistal support structure 265 or in a portion of the catheter 252 (notshown) that extends distally of the support structure 265. Similarly,the sensor component 276 extends through the passive portion 260 of thecatheter 252, through the passageway 274 of the proximal supportstructure 264, and through the through the steerable portion 262 of thecatheter 252. The sensor 276 may terminate in the passageway 282 of thedistal support structure 265 or in a portion of the catheter 252 (notshown) that extends distally of the support structure 265. The sensorcomponent 268 extends through the passageway 266 of the proximal supportstructure 264 but may be terminated proximally of steerable portion 262to allow the steerable portion to navigate smaller anatomical bodypassageways.

The steering wires 272 are controlled by a drive system (e.g. the drivesystem 208). The drive system 208 may be incorporated as part ofmanipulator 102. Examples of drive systems and flexible surgicalinstruments with remote control steering mechanisms are described inU.S. Pat. No. 7,942,868, filed Jun. 13, 2007, entitled “SurgicalInstrument With Parallel Motion Mechanism;” U.S. Pat. App. Pub. No.2010/0331820, filed Jun. 30, 2009, entitled, “Compliant SurgicalDevice;” and U.S. Pat. App. Pub. No. 2010/0082041, filed Sep. 30, 2008,entitled “Passive Preload and Capstan Drive for Surgical Instruments,”the full disclosures of which are all incorporated by reference hereinin their entirety. In various alternatives, the catheter 252 may benon-steerable with no integrated mechanism for operator control of theinstrument bending, in which case, the steering wires 272 and theirassociated passageways may be omitted.

In this embodiment, the sensor component 268 can be an electromagnetic(EM) sensor component that includes one or more conductive coils thatmay be subjected to an externally generated electromagnetic field. Eachcoil of the EM sensor component 268 then produces an induced electricalsignal having characteristics that depend on the position andorientation of the coil relative to the externally generatedelectromagnetic field. In one embodiment, the EM sensor system may beconfigured and positioned to measure six degrees of freedom, e.g., threeposition coordinates X, Y, Z and three orientation angles indicatingpitch, yaw, and roll of a base point. These measurements are gathered bya tracking system (e.g., tracking system 206). Alternatively the EMsensor system may sense fewer degrees of freedom. Further description ofan EM sensor system is provided in U.S. Pat. No. 6,380,732, filed Aug.11, 1999, disclosing “Six-Degree of Freedom Tracking System Having aPassive Transponder on the Object Being Tracked,” which is incorporatedby reference herein in its entirety. If implemented as a six-degree offreedom EM sensor, size constraints may limit placement of sensorcomponent 268 to the passive portion 260 of catheter 252 (e.g., withinor adjacent to proximal support structure 264) to allow the diameter ofsteerable portion 262 to be minimized for accessing smaller body lumens.

The sensor component 276 can include an optical fiber extending at leastpartially within the passageways 274, 282. The tracking system 206 iscoupled to a proximal end of the sensor component 276. In thisembodiment, the fiber has a diameter of approximately 200 μm. In otherembodiments, the dimensions may be larger or smaller.

The optical fiber of the sensor component 276 forms a fiber optic bendsensor for determining the shape of the steerable catheter portion 262.In one alternative, optical fibers including Fiber Bragg Gratings (FBGs)are used to provide strain measurements in structures in one or moredimensions. Various systems and methods for monitoring the shape andrelative position of an optical fiber in three dimensions are describedin U.S. patent application Ser. No. 11/180,389, filed Jul. 13, 2005,disclosing “Fiber optic position and shape sensing device and methodrelating thereto;” U.S. Provisional patent application Ser. No.12/047,056, filed on Aug. 10, 2010, disclosing “Fiber-optic shape andrelative position sensing;” and U.S. Pat. No. 6,389,187, filed on Jun.17, 1998, disclosing “Optical Fibre Bend Sensor,” which are incorporatedby reference herein in their entireties. In other alternatives, sensorsemploying other strain sensing techniques such as Rayleigh scattering,Raman scattering, Brillouin scattering, and Fluorescence scattering maybe suitable.

In this embodiment, the optical fiber of the shape sensor 276 mayinclude multiple cores within a single cladding. Each core may besingle-mode with sufficient distance and cladding separating the coressuch that the light in each core does not interact significantly withthe light carried in other cores. In other embodiments, the number ofcores may vary or each core may be contained in a separate opticalfiber.

In some embodiments, an array of FBG's is provided within each core.Each FBG comprises a series of modulations of the core's refractiveindex so as to generate a spatial periodicity in the refraction index.The spacing may be chosen so that the partial reflections from eachindex change add coherently for a narrow band of wavelengths, andtherefore reflect only this narrow band of wavelengths while passingthrough a much broader band. During fabrication of the FBG's, themodulations are spaced by a known distance, thereby causing reflectionof a known band of wavelengths. However, when a strain is induced on thefiber core, the spacing of the modulations will change, depending on theamount of strain in the core. Alternatively, backscatter or otheroptical phenomena that vary with bending of the optical fiber can beused to determine strain within each core.

Thus, to measure strain, light is sent down the fiber, andcharacteristics of the returning light are measured. For example, FBG'sproduce a reflected wavelength that is a function of the strain on thefiber and its temperature. This FBG technology is commercially availablefrom a variety of sources, such as Smart Fibres Ltd. of Bracknell,England. Use of FBG technology in position sensors for robotic surgeryis described in U.S. Pat. No. 7,930,065, filed Jul. 20, 2006, disclosing“Robotic Surgery System Including Position Sensors Using Fiber BraggGratings,” which is incorporated by reference herein in its entirety.

When applied to a multicore fiber, bending of the optical fiber inducesstrain on the cores that can be measured by monitoring the wavelengthshifts in each core. By having two or more cores disposed off-axis inthe fiber, bending of the fiber induces different strains on each of thecores. These strains are a function of the local degree of bending ofthe fiber. For example, regions of the cores containing FBG's, iflocated at points where the fiber is bent, can thereby be used todetermine the amount of bending at those points. These data, combinedwith the known spacings of the FBG regions, can be used to reconstructthe shape of the fiber.

As described, the optical fiber of the shape sensor 276 is used tomonitor the shape of the steerable portion 262 of the catheter 252. Morespecifically, light passing through the optical fiber is processed bythe tracking system 206 for detecting the shape of the portion 262 andfor utilizing that information to assist in surgical procedures. Thetracking system 206 may include a detection system for generating anddetecting the light used for determining the shape of the catheterportion 262. This information, in turn, in can be used to determineother related variables, such as velocity and acceleration of the partsof a surgical instrument. By obtaining accurate measurements of one ormore of these variables in real time, the controller can improve theaccuracy of the robotic surgical system and compensate for errorsintroduced in driving the component parts. The sensing may be limitedonly to the degrees of freedom that are actuated by the robotic system,or may be applied to both passive (e.g., unactuated bending of the rigidstructures between joints) and active (e.g., actuated movement of theinstrument) degrees of freedom.

The probe 258 is sized to extend through the passageway 256 of thecatheter 252 to capture images of the patient anatomy distal of thecatheter. The probe 258 includes an elongated flexible body 284 having aproximal end 286 and a distal end 288 which includes a distal tip. Inone embodiment, the flexible body 284 has an approximately 2 mm outerdiameter. In other embodiments, the flexible body 284 outer diameter maybe larger or smaller. The flexible body 284 may be formed from atransparent, semi-transparent, or opaque material. The flexible body 284includes a channel 290 that runs longitudinally along at least a portionof the length of the flexible body. An image capture instrument 292extends within the channel 290. A sensor component 294 also extendsthrough the channel 290. As shown in FIG. 3e , the probe 258 optionallyincludes an alignment support structure such as rigid alignment frame296 through which the sensor component 294 extends. The alignment frame296 may extend within a portion of the channel 290 and is supported bythe body 284. Similar to the alignment support structures, the rigidframe 296 controls the placement of the sensor component 294 relative tothe body 284 and relative to the image capture instrument 292. In thisembodiment, the sensor component 294 is generally axially aligned withthe image capture instrument 292 along the central axis A2 of the body284 and is positioned proximally of the image capture instrument. Thesensor component 294 may be adhered to the frame 296 to preventmovement. Optionally, other operational components, such as illuminationdevices or discrete fluid conduits (not shown), may extend within thechannel 290. In one aspect, the remaining portion of the channel 290,not occupied by the instrument 292 or any other operational components,may be a flow channel for delivering fluid to or from the distal end 288of the probe 258. Further description of various embodiments of probesare described in U.S. Provisional Application No. 61/658,305, filed Jun.11, 2012, entitled “Systems and Methods for Cleaning a MinimallyInvasive Instrument,” which is incorporated by reference herein in itsentirety.

The image capture instrument 292 includes a stereoscopic or monoscopiccamera disposed near the distal end 288 of the flexible body 284 forcapturing images that are transmitted to and processed by an imagingsystem (e.g., imaging system 204) for display. The imaging system 204may be incorporated as part of visualization system 110 and displaysystem 111. The image capture instrument 292 includes cabling andvarious mechanical, optical, and electrical couplings (not shown) forinterfacing with the imaging system 204. Alternatively, the imagecapture instrument may be a coherent fiber-optic bundle, such as afiberscope, that couples to the imaging system. The image captureinstrument may be single or multi-spectral, for example capturing imagedata in the visible spectrum, or capturing image data in the visible andinfrared or ultraviolet spectrums. In other various alternatives, theimage capture instrument 292 may wirelessly communicate image data tothe imaging system 204.

The sensor component 294 can be an EM sensor component that includes oneor more conductive coils that may be subjected to an externallygenerated electromagnetic field. Each coil of the EM sensor component294 then produces an induced electrical signal having characteristicsthat depend on the position and orientation of the coil relative to theexternally generated electromagnetic field. In one embodiment, the EMsensor system may be configured and positioned to measure five degreesof freedom of a base point. These measurements are gathered by thetracking system 206. Alternatively the EM sensor system may sense feweror more degrees of freedom. Further description of an EM sensor systemis provided in the previously incorporated by reference U.S. Pat. No.6,380,732. The five degree-of-freedom EM sensor component 294 may besmaller than the six degree-of freedom EM sensor 268, thus permittingthe probe 258 to have a diameter small enough to extend through thepassageway 256 of the catheter 252.

The tracking system 206 can use information received from the catheterEM sensor component 268, the shape sensor component 276, and optionallythe probe sensor component 294 in determining the position, orientation,speed, pose, and/or shape of the steerable portion 262 of the catheter252, the image capture instrument 292, a distal tip of the probe 258,and/or other components or portions of the catheter 252. The trackingsystem 206 may be implemented as hardware, firmware, software or acombination thereof which interact with or are otherwise executed by oneor more computer processors, which may include the processors of acontrol system 116.

The information from the tracking system 206 may be combined withconcurrent information from the visualization system 110 and/or thepreviously recorded patient images to provide the surgeon or otheroperator with real-time position information on the display system 111for use in the control of the system 250. The control system 116 mayutilize the position information as feedback for positioning thecatheter 252. Various systems for using fiber optic sensors to registerand display a surgical instrument with surgical images are provided inU.S. patent application Ser. No. 13/107,562, filed May 13, 2011,disclosing, “Medical System Providing Dynamic Registration of a Model ofan Anatomical Structure for Image-Guided Surgery,” which is incorporatedby reference herein in its entirety.

Any geometric variability in the relative separation between the varioussensors or between the sensors and the steering wires affects theaccuracy of the pose and shape information calculated using the combineddata from the EM sensors and the shape sensor. Inaccuracies in the poseand shape information may cause errors in the control signalssubsequently provided to move the steering wires. These inaccuracies mayfurther cause error in the registration of the catheter and probe toanatomical images of the patient. The passageways in the proximal anddistal support structures 264, 265 of the catheter 252 and the frame 296of the probe 258 tightly control the relative geometrical placement ofthe sensors 268, 276, 294 and the steering wires 272. Controlling therelative alignment of the sensors and the steering wires reduces thegeometric variability that would otherwise occur as the catheter andprobe are maneuvered through tortuous anatomical lumens. Reducing thisvariability may improve the accuracy of the pose and shape calculationsthat rely upon assumptions about the relative locations of the sensorsand steering wires.

Accurate registration of the catheter 252 and probe 258 to images of apatient anatomy (including prerecorded, schematic, or concurrent images)are based upon assumptions about the position of the sensors 268, 276,294 and the relative motion of the sensors. For the assumptions to beaccurate, the relative sensor poses should be accurately determined. Asdescribed above, the construction of the support structures 264, 265with dedicated passageways and the probe 258 with frames, serves toprovide reliable information about the relative sensor poses, positions,and/or orientations.

In the embodiment described above, to provide reliable information, theshape sensor component 276 may be held in a fixed lateral positionrelative to the catheter 252. Further, the shape sensor component 276may be maintained in a fixed pose relative to the sensor component 268,although longitudinal sliding may be permitted. Additionally, the shapesensor component 276 may be maintained in a fixed pose relative to thedistal end and particularly the distal tip of the catheter 252. Further,the sensor component 294 may be maintained in a fixed pose relative tothe distal tip of the probe 258 and is generally aligned collinearlywith the central axis of the probe (which is collinear with axis A2 whenthe probe 258 is inserted into the operational passageway 256.Alternatively, the sensor component 294 may be disposed in a differentknown configuration within the probe 258, such as parallel to thecentral axis of the probe. In alternative embodiments, the sensorcomponents of the probe or catheter may be held in fixed positions,orientations, or poses relative to various locations on the catheter,probe, or specific operational components of the catheter or probe.Further, the sensor components may be held in alignment with variousother operational components of the catheter or probe.

The mechanical tolerances for the passageways of the support structuresand the frame of the probe may vary depending upon the needed accuracy.In various specific embodiments, suitable tolerances are describedbelow. For example, in various embodiments, the shape sensor component276 may be maintained in a fixed position (e.g., less than approximately1 mm variation) and fixed orientation (e.g., less than approximately 1degree of rotation variation) at a point of the shape sensor componentclosest to the EM sensor component 268. In various embodiments, the samepositioning/orientation of the shape sensor component 276 relative tosteering wires 272 at the distal end region of catheter 250 can bemaintained by support structure 265. In various embodiments, the shapesensor component 276 may be maintained in a fixed lateral position(e.g., less than approximately 0.5 mm variation) and pitch/yaworientation (e.g, less than approximately 0.5 degree of rotationvariation) relative to the EM sensor component 268. In variousembodiments, the amount of roll induced on the shape sensor component276 between the EM sensor component 268 and the tip of the catheter 252may be maintained at less than approximately 5 degrees duringarticulation. For example, the sensor component 276 may have crosssection shaped like a key structure that matches a key-hole shape inpassageways 274/282 to limit the roll movement (e.g., rotation aroundthe Z-coordinate direction) of the sensor 276. In various embodiments,the distal end of the shape sensor component 276 may be maintained at afixed position (e.g., approximately less than 0.5 mm variation)approximately 2 mm or less from the distal tip of the catheter. Invarious embodiments, the EM sensor component 294 may be maintained in afixed position (e.g., less than approximately 1 mm variation) and fixedorientation (e.g., less than approximately 10 degrees of variation)relative to the distal end of the probe 258. In various embodiments, thelongitudinal axis of the EM sensor component 294 may be fixedcollinearly (e.g., within approximately less than 0.5 mm andapproximately less than 5 degrees of variation) with the central axis ofthe probe. In various embodiments, the shape sensor component 276 mayhave a lateral position relative to the steering wires that varies lessthan approximately 1 mm. In various embodiments, the shape sensorcomponent 276 may have a lateral distance relative to the EM sensorcomponent 268 that varies less than approximately 1 mm. In variousembodiments, the shape sensor component 276 may have a lateral positionrelative to the distal tip of the catheter 252 that varies by less thanapproximately 1 mm.

In various alternative embodiments, the alignment support structures maybe integrated with the catheter. For example, a section of the catheternear the steerable portion (e.g., immediately distal or proximal of thesteerable portion) may be precision extruded or precision machined toform tightly tolerance passageways in the catheter. Alternatively, rigidsupport structures may be inserted into the catheter for fixing thesensor components. The inserted support structures may be held in placeby an adhesive, a friction fit, or other known methods of adherence.

An alternative embodiment of a proximal support structure is illustratedin FIGS. 4 and 5. In this embodiment, a proximal support structure 300has a body wall 302 through which a passageway 304 extends. Thepassageway 304 includes a circumferential boundary 306 and is sized forthrough passage of a probe (e.g., probe 258) and is centrally alignedabout an axis A3. A passageway 308 extends through the body wall 302 andis radially offset from and generally parallel to the axis A3. Thepassageway 308 is sized to mate with a sensor component such as sensorcomponent 268. The support structure 300 further includes a groove 310sized to mate with the sensor component 276. The groove 310 maygenerally retain the sensor component 276 near the circumferentialboundary 306, limiting or restricting lateral motion (X-Y coordinatedirections) of the sensor component within the passageway 304. Thesensor component 276 may slide or rotate within the groove 310. Thesupport structure 300 further includes grooves 312 sized to receivesteering wires 272. The grooves 312 may generally retain the steeringwires 272 near the circumferential boundary 306, limiting or restrictinglateral motion of the sensor component within the passageway 304 towardthe axis A3 or radially about the axis A3. The steering wires 272 mayslide or rotate within the grooves 312. The support structure 300 mayfurther include ports 314 through which an adhesive material (not shown)may be placed to adhere the sensor component 268 to the supportstructure 300 to prevent or limit motion of the sensor componentrelative to the support structure. Note that while various grooves (310,312) and passageways (304) are depicted and described as an alignmentfeatures for exemplary purposes, in various other embodiments, suchalignment features can include any combination of passageways, notches,grooves, ridges, pockets, or any other features within or on aninternal/external surface of body wall 302.

Referring now to FIG. 6, a method 400 of operating an endoscopy systemincludes at 402, providing a catheter with an alignment supportstructure. The method also includes at 404, providing a first sensorcomponent extending within and laterally fixed with respect to thesupport structure. Optionally, at 406, a steering component, such assteering wires, are provided to extend within the support structure. Thesteering wires are laterally fixed with respect to the supportstructure. At 408, a probe is provided. A second sensor componentextends within the probe and has a fixed pose relative to the tip of theprobe. The method 400 includes, at 410, acquiring data from the firstsensor component. At 412, data is acquired from the second sensorcomponent. At 414, the pose of the distal tip of the probe, inthree-dimensional space, is determined with the data from the first andsecond sensor components. In some embodiments, the determination of 414is performed using a relative position and/or orientation of the firstand second sensors (with respect to each other and/or with respect to acentral axis of the catheter) defined by the support structure. The poseof the distal tip of the probe can be registered with an image of thepatient anatomy to provide the surgeon with accurate navigationinformation for moving the catheter and probe within the patientanatomy.

FIG. 7 illustrates a distal end of a probe 500 according to anembodiment of the disclosure. The probe 500 may be used as analternative to probe 258 for use within the system 250. The probe 500 issimilar to the probe 258, with the differences to be described. In thisembodiment, the probe 500 includes an elongated flexible body 502. Theflexible body 502 includes a longitudinal channel 504 in which an imagecapture instrument 506 extends. A sensor component 508 also extendsthrough the channel 504. The sensor component 508 is illustratedschematically and may be positioned in any of a variety of ways withinthe channel 504.

The probe 500 optionally includes support structures within the channelto support the image capture instrument and/or sensor component 508 in afixed lateral position within the channel. The support structures may beconstructed to hold the sensor component 508 and the image captureinstrument 506 in different spatial relationships relative to each otheror to the body 502, including coaxial, non-coaxial, parallel alignmentsor angled relationships. Optionally, other operational components, suchas illumination devices or discrete fluid conduits (not shown), mayextend within the channel 504. Further description of various componentsand embodiments of probes are described in the previously incorporatedby reference U.S. Provisional Application No. 61/658,305.

Although the systems and methods have been described herein with respectto endoluminal probes, the systems and methods are also suitable forother applications in which in vivo cleaning of an instrument isadvantageous. For example, the fluid delivery and cleaning systems andmethods described may be suitable for use with ablation catheters, laserfibers, other minimally invasive instruments, or other types ofendoscopic devices.

One or more elements in embodiments of the invention may be implementedin software to execute on a processor of a computer system such ascontrol system 116. When implemented in software, the elements of theembodiments of the invention are essentially the code segments toperform the necessary tasks. The program or code segments can be storedin a processor readable storage medium or device that may have beendownloaded by way of a computer data signal embodied in a carrier waveover a transmission medium or a communication link. The processorreadable storage device may include any medium that can storeinformation including an optical medium, semiconductor medium, andmagnetic medium. Processor readable storage device examples include anelectronic circuit; a semiconductor device, a semiconductor memorydevice, a read only memory (ROM), a flash memory, an erasableprogrammable read only memory (EPROM); a floppy diskette, a CD-ROM, anoptical disk, a hard disk, or other storage device, The code segmentsmay be downloaded via computer networks such as the Internet, Intranet,etc.

Note that the processes and displays presented may not inherently berelated to any particular computer or other apparatus. The requiredstructure for a variety of these systems will appear as elements in theclaims. In addition, the embodiments of the invention are not describedwith reference to any particular programming language. It will beappreciated that a variety of programming languages may be used toimplement the teachings of the invention as described herein.

While certain exemplary embodiments of the invention have been describedand shown in the accompanying drawings, it is to be understood that suchembodiments are merely illustrative of and not restrictive on the broadinvention, and that the embodiments of the invention not be limited tothe specific constructions and arrangements shown and described, sincevarious other modifications may occur to those ordinarily skilled in theart.

What is claimed is:
 1. A catheter system comprising: an elongateflexible catheter, the elongate flexible catheter defining a centrallumen having a first longitudinal axis; a support structure mounted on aproximal portion of the elongate flexible catheter such that a proximalsurface of the support structure is coupled to a distal surface of theproximal portion of the elongate flexible catheter, wherein the supportstructure is more rigid than the elongate flexible catheter; a firstalignment feature configured to mate with a first sensor component; anda second alignment feature configured to mate with a second sensorcomponent, wherein the first alignment feature and the second alignmentfeature are offset from and extend parallel to a central longitudinalaxis of the support structure and wherein the first alignment feature isconfigured to fix the first sensor component relative to the secondalignment feature in at least one degree of freedom at the supportstructure.
 2. The catheter system of claim 1, further comprising: thefirst sensor component mated with the first alignment feature; and thesecond sensor component mated with the second alignment feature, whereinthe first sensor component is fixed relative to the second sensorcomponent in at least one degree of freedom at the support structure bythe first alignment feature.
 3. The catheter system of claim 1, whereinthe support structure further comprises a wall defining a working lumenhaving a second longitudinal axis, and wherein the second longitudinalaxis is parallel to the first longitudinal axis.
 4. The catheter systemof claim 3, wherein the elongate flexible catheter extends within theworking lumen.
 5. The catheter system of claim 3, wherein the workinglumen is coaxially aligned with the central lumen.
 6. The cathetersystem of claim 1, wherein the first sensor component includes a shapesensor and the second sensor component includes an electromagneticposition sensor.
 7. The catheter system of claim 6, wherein the firstsensor component and the second sensor component are laterally fixedwith respect to the support structure.
 8. The catheter system of claim1, wherein the second alignment feature is formed in an interiorpassageway wall of the support structure.
 9. The catheter system ofclaim 8, wherein second alignment feature is a groove formed in aninterior passageway wall of the support structure, the groove sized tomate with the first sensor component.
 10. The catheter system of claim1, wherein the first alignment feature is a passageway extending througha wall of the support structure, the support structure further includinga port that couples an exterior surface of the support structure to aninterior surface of the passageway.
 11. The catheter system of claim 1,further comprising an additional support structure, the additionalsupport structure comprising a third alignment feature and having anouter diameter that is smaller than an outer diameter of the supportstructure.
 12. The catheter system of claim 11, wherein the supportstructure is coupled to the additional support structure by a distalportion of the elongate flexible catheter, wherein the first sensorcomponent extends through the distal portion of the elongate flexiblecatheter to mate with the third alignment feature.
 13. The cathetersystem of claim 1, further comprising an elongated flexible probe sizedto extend within the elongate flexible catheter and the supportstructure.
 14. A catheter system comprising: an elongate flexiblecatheter, the elongate flexible catheter defining a central lumen havinga first longitudinal axis; a first support structure mounted on aproximal portion of the elongate flexible catheter such that a proximalsurface of the support structure is coupled to a distal surface of theproximal portion of the elongate flexible catheter, wherein the supportstructure is more rigid than the elongate flexible catheter; a firstalignment feature formed in the first support structure and configuredto mate with a first sensor component; a second alignment feature formedin the first support structure and configured to mate with a secondsensor component, wherein the first alignment feature and the secondalignment feature are offset from and extend parallel to a centrallongitudinal axis of the first support structure; a second supportstructure mounted on a distal portion of the elongate flexible catheter;a third alignment feature formed in the second support structure andconfigured to mate with the first sensor component; and a set ofsteering wires extending through the first support structure and intothe second support structure.
 15. The catheter system of claim 14,further comprising: the first sensor component mated with the firstalignment feature; and the second sensor component mated with the secondalignment feature, wherein the first sensor component is fixed relativeto the second sensor component in at least one degree of freedom at thefirst support structure by the first alignment feature.
 16. The cathetersystem of claim 14, wherein the steering wires extend through a firstset of steering wire passageways formed in the first support structure.17. The catheter system of claim 14, wherein the first alignment featurecomprises a groove formed in an interior passageway wall of the supportstructure.
 18. The catheter system of claim 17, wherein the secondalignment feature comprises a channel extending within a wall of thefirst support structure.
 19. The catheter system of claim 18, furthercomprising at least one port formed in the first support structure, theport connecting an exterior surface of the first support structure to aninterior surface of the channel.
 20. The catheter system of claim 14,wherein the first support structure and the second support structurehave a same cross-sectional shape.